Chemical oxygen demand (COD), permanganate value (PV) and total organic carbon (TOC) are indexes commonly used to measure the contents of organic pollutants in waters. COD and PV relate to pollutants that can be oxidized by oxidant under given conditions and it is the summation of reductive substances that can be deoxidized easily in water. Many organic pollutants, especially aromatic compounds, are difficult to be oxidized or completely oxidized by oxidant, especially for permanganate. So COD & PV ca...